docs: def vminus(vin):
      """
      Negate a double precision 3-dimensional vector.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/vminus_c.html
  
      :param vin: Vector to be negated. 
      :type vin: 3-Element Array of floats
      :return: Negated vector -v1.
      :rtype: 3-Element Array of floats
      """
      vin = stypes.toDoubleVector(vin)
      vout = stypes.emptyDoubleVector(3)
      libspice.vminus_c(vin, vout)
      return stypes.cVectorToPython(vout)